Using fsolve() for a function involving quad()?

[Minyu Chen]

Dear all:

I am sorry that the question might sound a bit silly.

I need to solve a function involving integration, so I think I need  
both quad()--for the integration and fsolve()--for the equation.  
However, the integrand involve the unknown.

For a trivial example, I want to solve: x+\int_{0}^{1}x*y dy=0

I was thinking of taking a function:

function w=f(y)
w=x.*y;
endfunction

Then I use another function:

function z=g(x)
z=quad('f',0,1)+x;
endfunction

Then I use: fsolve('g',0.5). But it didn't work.

The error message is that the "x" is not defined in my f function.  
However, I called "f" only in the function "g", and the x in the  
function "g" is already initialized as 0.5 in the searching. What  
went wrong?

Thank you very much.

Thanks,
Minyu Chen